Read the text. Choose the best word that fits the space.

In the Arctic, climate change is having a particularly devastating impact. Russia controls a significant portion of the Arctic, and warming temperatures are causing permafrost—the frozen soil that underlies much of Siberia—to thaw. This thawing is destabilizing infrastructure, leading to the collapse of buildings and roads, and is releasing methane, a potent greenhouse gas. Additionally, melting ice is opening up new shipping routes and opportunities for resource extraction, but it also threatens fragile ecosystems and indigenous communities that rely on the region’s 5. ______ resources.

• financial
• ecological
• natural
• urban